[MediaSession] Add playbackState attribute to Blink MediaSession and use it to determine playback s…

content/browser/media/session/mock_media_session_player_observer.cc

Index: content/browser/media/session/mock_media_session_player_observer.cc
diff --git a/content/browser/media/session/mock_media_session_player_observer.cc b/content/browser/media/session/mock_media_session_player_observer.cc
index 4166b6485e84242712a71439de46faf42f1ff36b..6261d0e31a9500be0c1ca8627d70f7c6b20bb7fd 100644
--- a/content/browser/media/session/mock_media_session_player_observer.cc
+++ b/content/browser/media/session/mock_media_session_player_observer.cc
@@ -8,7 +8,9 @@
 
 namespace content {
 
-MockMediaSessionPlayerObserver::MockMediaSessionPlayerObserver() = default;
+MockMediaSessionPlayerObserver::MockMediaSessionPlayerObserver(
+    RenderFrameHost* render_frame_host)
+    : MediaSessionPlayerObserver(), render_frame_host_(render_frame_host) {}
 
 MockMediaSessionPlayerObserver::~MockMediaSessionPlayerObserver() = default;
 
@@ -41,7 +43,7 @@ void MockMediaSessionPlayerObserver::OnSetVolumeMultiplier(
 }
 
 RenderFrameHost* MockMediaSessionPlayerObserver::GetRenderFrameHost() const {
-  return nullptr;
+  return render_frame_host_;
 }
 
 int MockMediaSessionPlayerObserver::StartNewPlayer() {